Wildfires each year cause billions of dollars worth of damage worldwide. As the name suggests, these types of fires originate in nature and use the natural vegetation of the area as fuel. In most cases, a wildfire starts in a remote forested area, which is not easily accessible by land. Moreover, the extensive size of most wildfires makes suppression and control quite difficult. As such, the infrastructure required, and the techniques applied to suppress a fire in a rural or urban setting are of little value when attempting to suppress a wildfire.
One of the main differences between fighting a wildfire, compared to an urban or rural fire, is the use of aircraft to suppress the fire. Both fixed-wing and rotary aircraft have been used for this purpose. Fixed wing aircraft outfitted to receive and drop a quantity of water are commonly referred to as airtankers, whereas rotary aircraft outfitted for the same purpose are referred to as helitack helicopters.
Airtankers are capable of transporting and dropping a large volume of liquid, with the largest aircraft in the fleet today, such as the Evergreen Supertanker, having a capacity of 24,000 gallons. Such a capacity is effective in delivering liquid to a large area on a single pass of the airtanker. However, onloading of airtankers has to take place either at an airfield, while the aircraft is stationary, or by skimming a lake or large river. As such, an airtanker may be forced to fly long distances to refill after dropping its load on a fire.
Helitack helicopters provide greater maneuverability compared to airtankers and thus can be used for more than just dropping water on a fire. For example, the ability of a helicopter to hover above the ground allows it to transport supplies to crews on the ground. The ability to hover also allows a helitack helicopter to take on a fire suppressing load from a resource that would be unavailable to an airtanker, such as a small lake or reservoir.
A liquid, such as water or water combined with a fire retardant material, is typically transported to a drop zone by either a Bambi bucket, or, airframe-mounted water tank or helitank. In the case of a helitank, the liquid is typically onloaded through a snorkel that is lowered from the helicopter into the liquid source. When not is use, the snorkel is attached to the fuselage, which presents some issues with respect to the aerodynamics and handling of the helicopter. In particular, these additions place the helicopter into what is known as restrictive status, which limits its airspeed, ability to carry passengers and perform multiple duties. Moreover, drop patterns for the liquid, other than a complete drop, are generally difficult to achieve with helitanks, since opening the door(s) causes the whole load to be dropped.
The water tanks on current helitack helicopters could be improved to provide a system that is easier to control, that does not impact the control and the aerodynamics of the helicopter and can provide different drop patterns depending on the situation.